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3 years ago

Which of the following indicates that an exothermic reaction has taken place?

Chemistry

2 answers:

Tomtit [17]3 years ago

4 0

<h2>Answer:</h2>

The option B is correct option. Which is release of heat and/or light energy .

<h3>Explanation:</h3>

According to the definition of exothermic reaction :

<em>An exothermic reaction is a chemical reaction that releases energy by light or heat.</em>

From definition option B (release of heat and/or light energy) indicates that an exothermic reaction has taken place.

mote1985 [20]3 years ago

4 0

Answer: Option (B) is the correct answer.

Explanation:

An exothermic reaction is defined as the chemical reaction in which there occurs release of heat.

For example, $A + B \rightarrow AB + Heat$

In an exothermic reaction, energy of reactants is more than the energy of products.

Whereas an endothermic reaction is defined as a chemical reaction in which heat is absorbed by reactant molecules.

For example, $A + B + Heat \rightarrow AB$

In endothermic reaction, energy of reactant molecules is less than the energy of products.

Thus, we can conclude that release of heat and/or light energy indicates that an exothermic reaction has taken place.

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A student ran the following reaction in the laboratory at 671 K: 2NH3(g) N2(g) + 3H2(g) When she introduced 7.33×10-2 moles of N

vaieri [72.5K]

Answer:

Kc = 8.05x10⁻³

Explanation:

This is the equilibrium:

2NH₃(g) ⇄ N₂(g) + 3H₂(g)

Initially 0.0733

React 0.0733α α/2 3/2α

Eq 0.0733 - 0.0733α α/2 0.103

We introduced 0.0733 moles of ammonia, initially. So in the reaction "α" amount react, as the ratio is 2:1, and 2:3, we can know the moles that formed products.

Now we were told that in equilibrum we have a [H₂] of 0.103, so this data can help us to calculate α.

3/2α = 0.103

α = 0.103 . 2/3 ⇒ 0.0686

So, concentration in equilibrium are

NH₃ = 0.0733 - 0.0733 . 0.0686 = 0.0682

N₂ = 0.0686/2 = 0.0343

So this moles, are in a volume of 1L, so they are molar concentrations.

Let's make Kc expression:

Kc= [N₂] . [H₂]³ / [NH₃]²

Kc = 0.0343 . 0.103³ / 0.0682² = 8.05x10⁻³

3 0

3 years ago

Hydrogen is an element with two naturally occurring isotopes: 2 H and 3 H. This means that 2 H, which has a mass number of 2, ha

Dmitry_Shevchenko [17]

Answer:

TRUE.

Explanation:

Mass Number is the sum of protons and neutrons present in the nucleus of an atom. Isotopy is a phenonmenon that occurs when atoms of same elements have different mass number (Number of neutrons).

2H isotope has 1 proton and 1 neutron.

3H isotope has 1 proton and 2 neutrons.

This meeans 2H isotope has fewer neutrons when compared to the 3H isotope. The correct option is TRUE.

8 0

3 years ago

Find mass of 3 moles of water

EleoNora [17]

Answer:

54 g

Explanation:

1 mole of water = H2O

mass of 1 mole of H2O= mass of h2 + mass of o

= 2× mass of h +mass of o

= 2×1+16 =18 g

1 mole of water = 18g

3moles of water = 18×3g= 54g

6 0

3 years ago

Oh no! Igor stepped on a piece of glass on the sidewalk in front of

Helen [10]

Answer: The correct sequence for the series of event would be.

1. Igor's toe is being cut by the glass.

2. The wound surrounding the injury becomes infected with bacteria from Igor's foot.

3. Antibodies and circulating white blood cells stick to the bacteria creating a large complex in the lymph vessel.

4. The bacteria enter his lymph system and travel towards a lymph node.

5. The complex becomes trapped in a lymph node and is engulfed by a phagocyte.

6. The bacteria is destroyed.

Explanation:

Whenever there is any cut or wound in the body and body encounters invasion of the foreign materials it considers it as harmful pathogen.

These pathogens when enters the body it is considered as antigen, it then travels to the lymphatic system.

These bacterial complex is then killed by the phagocytes and digested by the body.

In this way the complex is killed and the bacteria is destroyed.

8 0

4 years ago

How do I do this and what are the answers?

vodka [1.7K]

I cannot see your question to help you... sorry

6 0

3 years ago